This application claims the priority benefit of Taiwan application serial no. 90125046, filed Oct. 11, 2001.
1. Field of the Invention
The present invention relates to a chemical mechanical polishing (CMP) device. More specifically, the present invention relates to a CMP device having a wafer carrier.
2. Description of the Related Art
A chemical mechanical polishing method is a technology that can provide global planarization by using a polishing tool and an appropriate reagent.
FIG. 1 is a schematic side view of a conventional chemical mechanical polishing (CMP) device. FIG. 2 is a schematic top view of a conventional CMP device.
With reference to FIGS. 1 and 2, the conventional CMP device includes a polishing table 100, a wafer carrier 106, a polishing pad 102, a tube 110, and a pad conditioner 108. The wafer carrier 106 is used to hold a wafer 104 to be polished. The carrier 106 has a vacuum hole (not shown) for sucking the wafer 104 and has a retainer ring (not shown) for supporting the wafer 104. The polishing pad 102 is arranged on the polishing table 100. The tube 110 conveys a polishing slurry 110a to the polishing pad 102. The pad conditioner 108 has a plurality of diamond grits to scrape against the surface of the polishing pad 102 so as to remove the polishing slurry remained in the polishing pad 102. During the CMP process, the polishing table 100 and the wafer carrier 106 rotates in a predetermined direction and the wafer carrier 106 catches a back surface 104a of the wafer 104, with the front surface 104b of the wafer 104 being pressed on the polishing pad 102. The tube 110 continuously supplies the polishing slurry 110a to the polishing pad 102, such that a chemical reaction between the front surface 104b of the wafer 104 and the reagent in the polishing slurry 110a occurs while the pad 102 contacts with protruding portions on the wafer. Meanwhile, the polishing pad 102 mechanically polishes the wafer 104 by using the abrasive grains in the polishing slurry 110a to remove the protruding portions on the wafer. After the chemical and mechanical polishing process repeats several times, a smooth surface can be obtained.
In general, the polishing pad has a plurality of pits thereon which help to convey the polishing slurry and to polish the wafer. The pits have an average depth of 1-2 microns. However, the depth of the pit decreases as the number of the polished wafer increases, which may degrade the polishing performance. Further, during polishing, the pit of the polishing pad can be filled by the abrasive grains in the polishing slurry or the polished-off substance from the wafer such that the polishing characteristics disappear. Therefore, a pad conditioner 108 is needed for removing the fillings of the pits so as to recover the polishing characteristics, such as uneven surface of the pad 102.
However, the conventional CMP device has a discrete wafer carrier and a separate pad conditioner, which requires more space. Furthermore, it is difficult to maintain a conventional CMP device that has complicate configuration.
In one aspect of the present invention, a wafer carrier used for CMP consists of a wafer carrier and a pad conditioner, in which the space and the maintenance fee for the CMP device can be effectively reduced.
In order to achieve the above and other objects of the present invention, a wafer carrier having a polishing head and a pad conditioner is provided. The polishing head has a retainer ring at a bottom thereof to hold a wafer. The pad conditioner is fixed on one surface of the retainer ring. The pad conditioner can be in contact with one of the polishing pads of the chemical mechanical device.
Furthermore, a wafer carrier used for a chemical mechanical device comprising a polishing head and a pad conditioner is provided. The polishing head has a retainer ring at a bottom thereof to hold a wafer in the bottom of the polishing head. The pad conditioner is attached to side surfaces of the polishing head. One conditioning surface of the pad conditioner is roughly parallel to one surface of the retainer ring. The pad conditioner can be in contact with one of the polishing pads of the chemical mechanical device.
Also, a wafer carrier used for a chemical mechanical device comprising a polishing head and a pad conditioner is provided. The polishing head has a retainer ring at a bottom thereof to hold a wafer. The pad conditioner is embedded in the retainer ring. The pad conditioner can be in contact with one of the polishing pads of the chemical mechanical device.